Conduit of varying lengths, diameters and materials of composition plays an integral role in contemporary industrial, technological society. The conduit includes pipe and tubing that is straight, flexible and corrugated, and can be copper, galvanized or, predominantly, of a durable, long-lasting plastic composition such as polyethylene, ABS, or PVC. Such conduit has wide applicability as water and sewerage lines and as protective channels for electrical wires.
Plastic pipe has long been manufactured by a process in which internal air pressure was pumped inside to push the plastic material outwardly to form the pipe. Using this method the plastic pipe was crimped closed and cut at desired lengths holding the internal air pressure inside. Thus, the pipe consumer is accustomed to hearing the air pressure escape when the crimp is cut off when the pipe is being installed. This escaping air is expected by the customer indicating that the pipe is intact.
More recently, plastic pipe has been manufactured by an extrusion and vacuum-forming process wherein the pipe comes off an extruder machine, the vacuum is used to pull the plastic outwardly to form the pipe, and, the pipe is cut to the desired length, and wound in coils. As there is no crimping, and there is no internal air pressure present; there is no escaping air sound upon installation as the customer has come to expect. The signal that the pipe is airtight and free of defects is missing. At the installation site, the pipe is not closed so there is no release of air giving an audible signal thereby assuring the end user that the integrity of the pipe has been maintained. It is of critical importance that the integrity of the pipe be maintained from the factory to the job site, and that direct confirmation of the pipe integrity can be provided to the end user as even the most minute crack or fissure will render that length or segment of pipe unusable for many uses. The prior art discloses numerous systems, techniques, and devices for closing, sealing and pressurizing orifices, conduit, or conduit networks of various kinds.
For example, the Larsen Patent (U.S. Pat. No. 1,702,972) discloses an apparatus for injecting alcohol into frozen gas pipe to unfreeze the pipe, and includes a flow control valve mounted within a casing that is threaded onto the T-coupling of the gas pipe so that an alcohol syringe can be brought into flow communication with the gas pipe for injection of the alcohol.
The Foster Patent (U.S. Pat. No. 2,321,667) discloses a stopper for gas pipe wherein the stopper includes a plug insertable into the end of the pipe and a cylindrical sleeve that passes over the outside of the pipe thereby closing off the end of the pipe.
The Lockhart Patent (U.S. Pat. No. 2,577,780) discloses a cupped resilient plug having circumferential ridges and grooves that define a chamber for the ingress or egress of fluid by, for example, a hypodermic needle.
The Fueslein et al. Patent (U.S. Pat. No. 3,200,984) discloses a pressure seal plug for sealing the bore of a tube, and includes a cylindrical body portion having an inner cavity for pushing the plug into the tube bore and external deformable ribs that seal against the inside surface of the tube as the plug is forced therein.
The Wilson Patent (U.S. Pat. No. 3,233,727) discloses a pressurized container for tennis balls wherein the container includes a cap having an integral air valve through which an air needle can be inserted for the injection or withdrawal of air into or from the container to maintain the contents within under positive or negative pressure.
The Palmer et al. Patent (U.S. Pat. No. 3,358,869) discloses a vacuum sealing plug that includes annular external ring portion on the plug body for sealing against the inside surface of the tube.
The Noble Patent (U.S. Pat. No. 3,362,225) discloses a pressure testing apparatus for testing fire hoses and the like by attaching one end of the hose to the apparatus and plugging the other end of the hose, and then directing water into the apparatus for pressure testing.
The Miller Patent (U.S. Pat. No. 3,574,312) discloses a flexible and elastic closure that can be placed over the end of a pipe for closing off that end, or the closure can be inserted into the bore of the pipe for blocking the bore and preventing fluid flow therethrough.
The Seltzer Patent (U.S. Pat. No. 3,604,591) discloses a cylindrical stopper capable of receiving an expander that expands the stopper for plugging an opening or orifice.
The Mess et al. Patent (U.S. Pat. No. 4,016,696) discloses a plug for sealing holes in concrete walls and the plug includes a cylindrical and tapered body having a socket for receiving a rod so that the plug can be pushed into the hole for sealing the hole after the rod is removed.
The Foreman Patent (U.S. Pat. No. 4,241,919) discloses an aluminum baseball bat with a hollow interior and an end formed by a solid rubber plug whereupon a needle inserted into and through the plug can be used to vary the fluid pressure of the hollow interior of the bat.
The Hood Patent (U.S. Pat. No. 5,207,247) discloses a system and apparatus for plugging a tube and includes a major cylindrical portion for containing therein a push rod, a tapered minor cylindrical portion for insertion into the bore of the tube, and a conical-shaped, deformable and expansible stopper that is forced by the push rod through the tapered minor cylindrical portion and into the tube bore for plugging the bore.
The Ferguson Patent (U.S. Pat. No. 6,237,620 B1) discloses a tool for plumbing system maintenance and includes a tool for interconnection between an air compressor and a faucet so that compressed air can be introduced to purge the system and then anti-freeze can be introduced for winterization of the plumbing system.
Other Patents related to pressurizing, testing or plugging conduit or conduit networks include Japanese Patent PCT No. WO/92/15820 for detection and localization of leaks in a conduit system, Japanese Patent No. JP409141634A for pressurizing rubber hose so that caulking rings are inserted at both ends of the hose without protruding, UK Patent No. GB 2078899 for a plug for sealing an orifice wherein the plug includes an insert that expands during insertion for sealing the plug in the orifice, and French Patent No. FR002657673A1 for a method for pressurizing PVC pipe without deformation or damage to the pipe.
Nonetheless, despite the ingenuity of the above systems and devices, there remains a need for a pipe pressurization method and apparatus that is easy to manipulate, adaptable for various conduit types and diameters, and provides an immediate signal to the end user that pipe integrity has been maintained.